The present invention relates to microemulsions capable of killing insects without the use of conventional insecticides. It is particularly useful in killing crawling insects that have hard, waxy exoskeletons.
Hydrocarbon solvents assist in insect knock-down. Unfortunately, many hydrocarbons are flammable and as a result conventional insect control agents are sometimes delivered via oil/water type emulsions. See e.g. U.S. Pat. No. 5,145,604. The disclosure of this patent, and of all other publications referred to herein, are incorporated by reference as if fully set forth herein.
However, many prior art oil/water emulsions are unstable. The user must shake the container shortly before use to recreate the emulsion on a temporary basis. The art therefore developed much more stable microemulsions containing water, hydrocarbon, conventional insecticide, and one or more emulsifiers. See e.g. U.S. Pat. No. 5,037,653. For purposes of this application a "microemulsion" is a transparent, stable dispersion of oil and water where the dispersed phase consists mostly of small droplets with diameters between 10 and 100 millimicrons.
However, because such prior art insecticides contain conventional insecticidal actives, they are subject to stringent regulatory control, have a relatively high cost, have limitations on their use (e.g. not too close to food), and are sometimes perceived by the public as environmentally undesirable.
Some have tried applying surfactant solutions directly to insects as a more natural insecticide approach. See e.g. U.S. Pat. No. 5,489,433. However, this approach is not very effective against hard body insects such as cockroaches.
Thus, a need exists for improved, environmentally safe insect control compositions.